floof/lib/tags.py

   1 from floof.model import Art, ArtUser, ArtUserType, Tag, TagText, User
   2
   3 def parse(search_string):
   4     """Parses a search query, and returns a query object on Art.
   5
   6     Queries can contain:
   7     - Regular tags: foo
   8     - User relations: by:kalu, of:eevee, for:ootachi
   9
  10     Later:
  11     - Negative versions of anything above: -by:eevee, -dongs
  12     """
  13
  14     # XXX doesn't do negative querying yet.
  15     # XXX could use some sane limits.
  16
  17     # We'll be building this as we go.
  18     q = Art.query
  19
  20     terms = search_string.split()
  21     for tag in terms:
  22         if ':' in tag:
  23             # This is a special tag; at the moment, by/for/of to indicate
  24             # related users
  25             prefix, tag = tag.split(':', 1)
  26
  27             # XXX what to do if this fails?  abort?  return empty query?
  28             target_user = User.get_by(name=tag)
  29
  30             if prefix == 'by':
  31                 rel = ArtUserType.BY
  32             elif prefix == 'for':
  33                 rel = ArtUserType.FOR
  34             elif prefix == 'of':
  35                 rel = ArtUserType.OF
  36             else:
  37                 # Bogus tag.  Not sure what to do here, so for the moment,
  38                 # ignore it
  39                 continue
  40
  41             # Inner join to the ArtUser table
  42             q = q.join(ArtUser, aliased=True) \
  43                  .filter(ArtUser.user == target_user) \
  44                  .filter(ArtUser.type == rel)
  45
  46         else:
  47             # Regular ol' tag
  48             q = q.join(Tag, TagText, aliased=True) \
  49                  .filter(TagText.text == tag)
  50
  51     return q
  52
  53 def add_tags(art, tag_string, user):
  54     """Takes a string that looks like a tag query, and effectively modifies the
  55     art's tags to match it.
  56     """
  57
  58     # XXX what to do with invalid tags?  just return them and let caller fix?
  59     bad_tags = []
  60     for tag_text in tag_string.split():
  61         original_tag_text = tag_text
  62         tag_text = tag_text.lower()
  63
  64         # Adding or removing a tag?
  65         if tag_text[0] == '-':
  66             add = False
  67             tag_text = tag_text[1:]
  68         else:
  69             # Allow "+foo" to mean "add foo"
  70             if tag_text[0] == '+':
  71                 tag_text = tag_text[1:]
  72             add = True
  73
  74         # Check for special namespaces
  75         prefix = None
  76         if ':' in tag_text:
  77             prefix, tag_text = tag_text.split(':', 1)
  78             if prefix not in ['by', 'for', 'of']:
  79                 # This is bogus.  Skip it.
  80                 bad_tags.append(original_tag_text)
  81                 continue
  82
  83             if prefix == 'by':
  84                 # XXX this needs supporting.  silently ignore for now
  85                 continue
  86
  87         # Must be 3-50 alphanumeric characters
  88         if not re.match('^[a-z0-9]{3,50}$', tag_text):
  89             bad_tags.append(original_tag_text)
  90             continue
  91
  92         # Do work!
  93         if prefix:
  94             target_user = User.get_by(name=tag_text)
  95
  96             # Special tag; at the moment, just a relationship
  97             if prefix == 'by':
  98                 rel = ArtUserType.BY
  99             elif prefix == 'for':
 100                 rel = ArtUserType.FOR
 101             elif prefix == 'of':
 102                 rel = ArtUserType.OF
 103
 104             user_assoc_data = dict(art=art, user=target_user, type=rel)
 105             if add:
 106                 find_or_create(ArtUser, **user_assoc_data)
 107
 108             else:
 109                 # XXX this will die for nonassociations
 110                 user_assoc = ArtUser.get_by(art=art, **user_assoc_data)
 111                 user_assoc.delete()
 112
 113         else:
 114             # Regular tag
 115             if add:
 116                 tag = find_or_create(TagText, text=tag_text)
 117                 find_or_create(Tag, art=art, tagger=user, tagtext=tag)
 118
 119             else:
 120                 tag = TagText.get_by(text=tag_text)
 121                 if tag:
 122                     # XXX this will die
 123                     tag_assoc = Tag.get_by(art=art, tagger=user, tagtext=tag)
 124                     tag_assoc.delete()
 125
 126     elixir.session.commit()